I'm a bag-a-holic- and I just use whichever best suits my needs and mood at the time!!! I'm often in public places like the subway or a busy Mall, and totes are an invitation for pickpocketing. So, If you are going to use a tote or generally opened top bag, you may want to include some type of closure such as a snap or flap, so as to deterr theft. or put the valuables in a smaller closed bag.
I like bags with lots of pockets so I can stash the cell phone etc without having to dig around in a cavernous pile of stuff at the bottom of the bag.